1. Field of the Invention
This invention relates to a multiple exposure device for a camera and more particularly to a multiple exposure device which permits presetting a number of performance steps of a multiple exposure operation.
2. Description of the Prior Art
According to the conventional multiple exposure arrangement for a camera, the camera is set into a multi-exposure mode either by manually operating a multi-exposure operation member or by having it kept in a multi-exposure position by a lock device in response to the manual operation. A motor drive device is switched on to start a photo-taking operation. Then, the number of performances of multiple exposure are counted by the camera operator through the travelling sound of the shutter of the camera. The operator is required to switch off the motor drive device to bring the multiple exposure operation to a stop when the number of performances reach a desired number. However, in cases where the photo-taking is repeated in a quick cycle, it has been almost impossible to accurately count the number of exposure performances. It has been thus difficult for the operator to switch off the motor drive device in concurrence with the end of a desired number of multi-exposure performances.
In view of this shortcoming of the conventional multi-exposure arrangement, a camera arranged to permit presetting a desired number of multi-exposure performances and to perform film winding upon completion of the preset number of multi-exposure performances has been disclosed in Japanese Laid-Open Patent Application No. SHO 56-95231. However, it this camera does not display whether or not the film has already been exposed after presetting of the number of multi-exposure performances. Therefore, there has been the following inconvenience in the event of cancelling a multi-exposure operation during the process thereof after presetting of the number of multi-exposure performance steps. In case that the multi-exposure is cancelled when the film has been actually exposed to light after setting a multiple exposure, the film must be wound up for a next photo-taking operation. However, if the film is wound up while the film has not been actually exposed to light, one frame portion of the film would never be exposed. In that event, the film winding must be prevented. Whereas, the multi-exposure device of the conventional camera has not been arranged to make a display to show the operator whether the film has been exposed or not after presetting of a multi-exposure operation. It has thus been impossible to determine whether or not a film winding process must be performed at the time of cancelling the multi-exposure operation mode.
Further, to have a desired number of performances of multiple exposure accurately carried out, the camera disclosed in the above-cited Japanese Laid-Open Patent Application No. SHO 56-95231 is arranged as follows: A member which is controlling a film feeding operation is kept in a position not to allow film winding concurrently with a charging operation on a shutter when the shutter is charged. A counter is arranged to count the number of times for which a multiple exposure is performed. After commencement of a multi-exposure operation, when the counted values of the counter reaches a number of times which is a desired number of times minus one, the above-stated holding member is released from its holding operation on the film feeding control member by a shutter charging process performed at that time. Then, after completion of the last performance of the multiple exposure, film winding is performed concurrently with shutter charging in such a way as to automatically bring the multi-exposure operation to an end.
The camera disclosed in the above Japanese patent application is thus arranged to have the film feeding control member shifted from a position not allowing film feeding to another position allowing film feeding when the counted values of the counter counting the performances of multiple exposure for ending the process of multiple exposure reaches a value which is a desired number of performances minus one. Therefore, in cases where the multiple exposure mode is to be cancelled during the process of multiple exposure, the position of the film feeding control member cannot be shifted until the counted value of the counter reaches the value which is the desired number of performances minus one. This virtually prohibits the multiple exposure from being cancelled even when it becomes desirable to cancel the multiple exposure during the process thereof.
Further, with the conventional device used in carrying out multiple exposure for a preset number of performances, the camera is allowed to shift to a normal exposure mode after completion of multiple exposure without prohibiting a further process of exposure. Therefore, when film winding is performed after the multiple exposure, a normal photo-taking operation might immediately follow the film winding process to waste the film after the multi-exposure process.
The conventional multiple exposure device is arranged to have a desired amount or degree of exposure for each performance step of the multi-exposure operation preset by the camera operator. It has been, therefore, difficult to have the film appropriately exposed through all the exposures made for a multiple exposure.